Liquid crystal display devices are widely used as displays of portable electronic devices including cellular phones, or of televisions, personal computers, and so on. However, it is generally known so far that a liquid crystal display device has good viewability when looked from the front side, but its viewing angle is narrow. For that reason, various ideas have been proposed to widen the viewing angle. One of those ideas is to dispose a member (hereinafter referred to as a “light diffusion member”) for diffusing light emerging from a display main unit, including a liquid crystal panel, etc., on the viewing side of the display main unit.
For example, Patent Literature (PTL) 1, given below, discloses a light diffusion sheet including a light diffusion layer for diffusing light that is going to transmit through the sheet in the direction of thickness thereof. The disclosed light diffusion sheet includes a plurality of grooves formed to extend in parallel in a one-dimensional direction and having a substantially V-shaped cross-section, and a substance in the form of a black liquid or solid, the substance being filled in the grooves and having a lower refractive index than that of the light diffusion layer. The grooves are formed such that each groove is flared in the V-like shape toward an observing-side surface of the light diffusion sheet and a tip end of the V-shape is positioned in the light diffusion layer.